末次冰期最盛期以来长江扬中段古河谷的沉积环境

doi:10.7522/j.isnn.1000-0240.2015.0179

摘要/Abstract

摘要： 选择长江扬中段古河谷作为研究对象, 探讨末次冰期最盛期以来的沉积环境.搜集整理了扬中—泰州长江大桥地质勘探钻孔28个, 根据钻孔资料, 绘制了长江古河谷的地质剖面示意图.在其中2个钻孔采集了粒度样品、磁化率样品, 分别用Mastersizer 2000激光粒度仪、BartingtonMS2磁化率仪进行了分析; 在4个钻孔采集了¹⁴C年代样品, 利用液体闪烁计数仪进行测定, 得出了27个年代数据.结果表明: 扬中地区长江古河谷约-61 m以上沉积为末次冰期最盛期以来的沉积; 末次冰期最盛期、晚冰期早期(约12 000 a B.P.), 河流滞留沉积与溯源堆积形成了厚约24 m的河床相砂砾层; -23~-37 m为12 000 a B.P.-8 000 a B.P.时的河漫滩相沉积, 沉积物主要为粉砂及粉砂质黏土, 局部细砂; 8 000 a B.P.-4 000 a B.P.为河口湾环境, 形成河口湾-浅海沉积, 厚度为-17~-23 m, 沉积物主要为粉砂夹粉砂质黏土; -17 m以上为4 000年以来的河口坝、汊道河床沉积及三角洲形成以来的河床、河漫滩沉积.

关键词: 末次冰期最盛期, 长江扬中段, 古河谷, 沉积环境

Abstract: The Yangtze River incised-valley in the Yangzhong reach was selected as the research object to study the sedimentary environment since the Last Glacial Maximum. Cores of 28 geological exploration boreholes of the Yangzhong-Taizhou Yangtze River Bridge were collected and sorted out. Based on the drilling data, the stratigraphical cross-section of the Yangtze River incised-valley was drawn. In two of the boreholes, grain-size samples and magnetic susceptibility samples were collected, and then analyzed respectively by using Mastersizer 2000 laser particle size analyzer and Bartington MS2 magnetic susceptibility meter; samples for ¹⁴C dating were also collected in four of the boreholes and then were tested by liquid scintillation counter in State Key Laboratory of Lake Science and Environment affiliated to Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences. At last, 27 age data were obtained. It is concluded that the top 61-m deposition on the Yangtze River incised-valley in Yangzhong region belongs to the Last Glacial Maximum. The riverbed gravel layer, 24 m in depth, was formed in the Last Glacial Maximum and the Early Late Glacial (about 12 000 a B.P.) due to the lag deposits and headward accumulation of river. Floodplain deposits developed during 12 000-8 000 a B.P. lies at about -23~-37 m depth with the sediments mainly of silt and silty clay, partly fine sand. During about 8 000-4 000 a B.P. the Yangtze River incised-valley in Yangzhong region had presented estuary environment and developed estuarine-shallow marine deposits, -17~-23 m in depth, and the main components of sediments are silt mixed with silty clay. About -17 m above there are mouth bar and braided riverbed deposit since 4 000 years before and the riverbed, floodplain deposits since the formation of deltas.

Key words: Last Glacial Maximum, Yangzhong reach of the Yangtze River, paleo-valley, sedimentary environment

中图分类号:

P512

曹光杰, 张学勤, 吴婷, 闫克超, 曹原. 末次冰期最盛期以来长江扬中段古河谷的沉积环境[J]. 冰川冻土, 2015, 37(6): 1627-1633.

CAO Guangjie, ZHANG Xueqin, WU Ting, YAN Kechao, CAO Yuan. Sedimentary environment of the Yangtze River paleo-valley in Yangzhong reach since the LGM[J]. JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY, 2015, 37(6): 1627-1633.

参考文献

[1] Shen Yongping, Wang Guoya. Key findings and assessment results of IPCC WGI Fifth Assessment Report[J]. Journal of Glaciology and Geocryology, 2013, 35(5):1068-1076.[沈永平, 王国亚. IPCC第一工作组第五次评估报告对全球气候变化认知的最新科学要点[J]. 冰川冻土, 2013, 35(5):1068-1076.]
[2] Ren Jiawen. Updating assessment results of global cryospheric change from SPM of IPCC WGI Fifth Assessment Report[J]. Journal of Glaciology and Geocryology, 2013, 35(5):1065-1067.[任贾文. 全球冰冻圈现状和未来变化的最新评估:IPCC WGI AR5 SPM发布[J]. 冰川冻土, 2013, 35(5):1065-1067.]
[3] Zhang Wei, Liu Beibei. Features of the glaciation during the Last Glaciation in northwestern Yunnan Province[J]. Journal of Glaciology and Geocryology, 2014, 36(1):30-37.[张威, 刘蓓蓓. 滇西北山地末次冰期冰川发育及其基本特征[J]. 冰川冻土, 2014, 36(1):30-37.]
[4] Zhao Jingdong, Wang Jie, Yin Xiufeng. Quaternary glaciations research in China:current status and controversy[J]. Journal of Glaciology and Geocryology, 2013, 35(1):119-125.[赵井东, 王杰, 殷秀峰. 中国第四纪冰川研究的现状与争议:兼记首届"中国第四纪冰川与环境变化研讨会"[J]. 冰川冻土, 2013, 35(1):119-125.]
[5] Shi Yafeng, Zheng Benxing, Yao Tandong. Glaciers and environment during the Last Glacial Maximum (LGM) on the Qinghai-Tibetan Plateau[J]. Journal of Glaciology and Geocryology, 1997, 19(2):97-113.[施雅风, 郑本兴, 姚檀栋. 青藏高原末次冰期最盛时的冰川与环境[J]. 冰川冻土, 1997, 19(2):97-113.]
[6] Yang Huairen, Xu Xin, Yang Dayuan, et al. Environmental changes and ecosystem in the Yangtze River's middle and lower reaches[M]. Nanjing:Hohai University Press, 1995:92-93.[杨怀仁, 徐馨, 杨达源, 等. 长江中下游环境变迁与地生态系统[M]. 南京:河海大学出版社, 1995:92-93.]
[7] Institute of Geography, Chinese Academy of Sciences, Yangtze River Institute of Water Resources and Hydro-Power Research. Channel properties and evolution in the Yangtze River's middle and lower reaches[M]. Beijing:Science Press, 1985.[中国科学院地理研究所, 长江水利水电科学研究院. 长江中下游河道特性及其演变[M]. 北京:科学出版社, 1985.]
[8] Wang Pinxian, Sun Xiangjun. Last Glacial Maximum in China:comparison between land and sea[J]. Catena, 1994, 23(3/4):341-353.
[9] Yan Qinshang, Hong Xueqing. The transgression of northern plain in Yangtze Delta during Holocene Epoch[M]//Recent Yangtze delta deposits. Shanghai:East China Normal University Press, 1987:92-102.[严钦尚, 洪雪晴. 长江三角洲南部平原全新世海侵问题[M]//长江三角洲现代沉积研究. 上海:华东师范大学出版社, 1987:92-102.]
[10] Geng Xiushan. The transgression and regression since the late Pleistocene of east China[J]. Acta Oceanologica Sinica, 1981, 3(1):114-128.[耿秀山. 中国东部晚更新世以来的海水进退[J]. 海洋学报, 1981, 3(1):114-128.]
[11] Yang Dayuan. The paleoenvironment of the mid-lower regions of Changjiang in the full-glacial period of Late Pleistocene[J]. Acta Geograpinca Sinica, 1986, 41(4):302-310.[杨达源. 晚更新世冰期最盛时长江中下游地区的古环境[J]. 地理学报, 1986, 41(4):302-310.]
[12] Cao Guangjie, Wang Jian, Wang Lingjun, et al. Characteristics and runoff volume of the Yangtze River's paleovalley at Nanjing reach in the Last Glacial Maximum[J]. Journal of Geographical Sciences, 2010, 20(3):431-440.
[13] Cao Guangjie, Wang Jian, Li Yanyan. Sedimentary seqenceses of the Yangtze River paleo-valley near the No.4 Nanjing Bridge since LGM[J]. Journal of Stratigraphy, 2010, 34(4):389-393.[曹光杰, 王建, 李彦彦. 南京长江四桥附近长江古河谷沉积层序[J]. 地层学杂志, 2010, 34(4):389-393.]
[14] Cao Guangjie, Zhang Jinbao. The downcutting depth and sedimentary cycles of the Yangtze River's paleo-channel in the Xiaguan-Qixia Mountain reach since the Last Glacial Maximum[J]. Journal of Glaciology and Geocryology, 2011, 33(2):431-435.[曹光杰, 张金宝. 末次盛冰期以来长江下关-栖霞山段下切深度及沉积旋回[J]. 冰川冻土, 2011, 33(2):431-435.]
[15] Cao Guangjie, Cuan Jingbo, Li Yanyan. Characteristics of the Yangtze River paleo-valley in Jiangsu Province in the Last Glacial Maximum[J]. Scientia Geographica Sinica, 2012, 32(8):986-992.[曹光杰, 爨景波, 李彦彦. 长江江苏段末次盛冰期古河槽特征[J]. 地理科学, 2012, 32(8):986-992.]
[16] Li Congxian, Fan Daidu, Zhang Jiaqiang. Late quaternary stratigraphical framework and potential environmental problems in the Yangtze Delta area[J]. Marine Geology & Quaternary Geology, 2000, 20(3):1-7.[李从先, 范代读, 张家强. 长江三角洲地区晚第四纪地层及潜在环境问题[J]. 海洋地质与第四纪地质, 2000, 20(3):1-7.]
[17] Li Congxian, Zhang Guijia. Researches on high resolution sequence stratigraphy of the Yangtze Delta during late quaternary period[J]. Marine Geology & Quaternary Geology, 1996, 16(3):13-24.[李从先, 张桂甲. 晚第四纪长江三角洲高分辨率层序地层学的初步研究[J]. 海洋地质与第四纪地质, 1996, 16(3):13-24.]
[18] Li Congxian, Wang Pinxian. Researches on stratigraphy of the late Quaternary period in Yangtze River mouth[M]. Beijing:Science Press, 1988:111-160.[李从先, 汪品先. 长江晚第四纪河口地层学研究[M]. 北京:科学出版社, 1998:111-160.]
[19] Li Congxian, Chen Qingqiang, Fan Daidu, et al. Palaeogeography and palaeoenvironment in Changjiang Delta since last glaciation[J]. Journal of Palaeogeography, 1999, 1(4):12-25.[李从先, 陈庆强, 范代读, 等. 末次盛冰期以来长江三角洲地区的沉积相和古地理[J]. 古地理学报, 1999, 1(4):12-25.]
[20] Li Congxian, Wang Ping, Sun Heping, et al. Late Quaternary incised-valley fill of the Yangtze Delta (China):its stratigraphic framework and evolution[J]. Sedimentary Geology, 2002, 152:133-158.
[21] Chen Zhongyuan, Song Baoping, Wang Zhanghua, et al. Late Quaternary evolution of the sub aqueous Yangtze River Delta, China:sedimentation, stratigtraphy, palynology, and deformation[J]. Marine Geology, 2000, 162:423-441.
[22] Zhang Jiaqiang, Zhang Guijia, Li Congxian. Characteristics of the late Quaternary stratigraphic sequence in the Changjiang River Delta area[J]. Journal of Tongji University, 1998, 26(4):438-442.[张家强, 张桂甲, 李从先. 长江三角洲晚第四纪地层层序特征[J]. 同济大学学报, 1998, 26(4):438-442.]
[23] Xu Shiyuan, Wang Jingtai, Li Ping. The Evolution stage of the Yangtze River Delta[M]//Recent Yangtze Delta deposits. Shanghai:East China Normal University Press, 1987:264-277.[许世远, 王靖泰, 李萍. 论长江三角洲发育的阶段性[M]//长江三角洲现代沉积研究. 上海:华东师范大学出版社, 1987:264-277.]
[24] Wang Jingtai, Guo Xumin, Xu Shiyuan, et al. Evolution of the Holocene Changjiang Delta[J]. Acta Geologica Sinica, 1981, 55(1):67-81.[王靖泰, 郭蓄民, 许世远, 等. 全新世长江三角洲的发育[J]. 地质学报, 1981, 55(1):67-81.]
[25] Study Group on the Delta of the Marine Geology Department in Tongji University. The formed and growth of Yangtze delta in Holocene Epoch[J]. Chinese Science Bulletin, 1978, 23(5):310-314.[同济大学海洋地质系三角洲科研组. 全新世长江三角洲的形成和发育[J]. 科学通报, 1978, 23(5):310-314.]
[26] Yang Huairen, Xie Zhiren. Sea-level changes along the east coast of China over the last 20000 years[J]. Oceanologia et Limnologia Sinica, 1984, 15(1):1-13.[杨怀仁, 谢志仁. 中国东部近20000年来的气候波动与海面升降运动[J]. 海洋与湖沼, 1984, 15(1):1-13.]